The use of implantable fluid medication dispensers is well known. These devices typically include a medication reservoir within a generally cylindrically shaped housing. Some form of fluid flow control is also provided to control or regulate the flow of fluid medication from the reservoir to the outlet of the device for delivery of the medication to the desired location, usually through a catheter. The flow control may be provided by a pumping or metering device such as disclosed in U.S. Pat. No. 4,692,147 issued to Duggan. Other forms of flow control are disclosed in U.S. Pat. Nos. 3,951,147 and 4,360,019.
All implantable fluid medication dispensers must also include some means to replenish the fluid medication in the medication reservoir. The previously mentioned U.S. Pat. Nos. 4,692,147 to Duggan and 3,951,147 to Tucker et al. disclose typical reservoir refill assemblies. Both include an opening or port through which a resealable septum may be accessed. To refill the reservoir a hypodermic needle is inserted through the septum and into a chamber between the septum and a needle stop, which may be a plug or filter. The medication is injected under pressure into the chamber and flows into the Reservoir.
One disadvantage exists with respect to currently used fluid medication dispensers is the relatively large size of the devices. The external cover or housing must be made large enough to accommodate the fluid medication reservoir, the reservoir refill assembly and all of the associated electronic/control components necessary to the proper function of the device. In order to accommodate all of these internal components, medication dispensers have typically been bulkier than desired. Therefore, it would be desirable to provide a medication delivery device where the overall dimensions are reduced. In particular, it would be desirable to provide such a device with a reduced thickness.